Wireless access provides tetherless access to mobile users, this has been done principally to address the requirements of two specific and disjoint domains: voice telephony and indoor data LANs. Cellular telephone networks have extended the domain of telephone service over a wireless last hop, while mobile-IP LANs such as WaveLAN from AT&T, and RangeLAN from Proxim, do the same for indoor users of TCP/IP data networks. Advances with wireless technology and high-speed integrated service wired networking promises to provide mobile users with comprehensive multimedia information access in the near future.
Personal Communication Services (PCS) are a broad range of individualized telecommunication services which enable individuals or devices to communicate irrespective of where they are at anytime. Personal Communication Networks (PCN) are a new type of wireless telephone system communicating via low-power antennas. PCNs offer a digital wireless alternative to the traditional wired line.
As a cellular mobile radio moves from one cell to another, it is "handed" off to the next cell by a controller, which determines which cell is receiving the strongest signal. Because the cellular user remains closer to the base transceiver than in classical mobile communications, the cellular user's transceiver requires less power and is therefore less expensive. The great advantage of the cellular concept over non-cellular radio is that higher capacity is allowed with the same frequency allocation. This advantage comes at a cost, the necessity of a large number of cell sites and associated radio ports. The switching from one cell to an adjacent cell site requires the accurate knowledge of the availability of the radio ports and their locations.
Cellular and PCS technologies that are based on Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) require some form of channel assignment scheme to divide spectrum amongst users. In the earlier systems channel assignment was based on a fixed channel reuse plan. This Fixed Channel Assignment (FCA) is known to serve uniform and heavy traffic satisfactorily. However when the traffic pattern is non-uniform a channel assignment scheme that assigns channels dynamically has the potential to serve users more efficiently. FCA, while being straight forward to implement, requires elaborate cell-site engineering and manual processes to install the system. Due to these reasons spectrum management in cellular systems have started to migrate toward dynamic channel assignment schemes.
It is advantageous to automate the allocation of a channel within a cell to optimize performance in order to improve the overall quality of the operation of the cell site. While some causes of channel interference can be long term in duration such as terrain features, system deployment (which includes base station layout, antenna types and configurations, etc.) and fixed spectrum, other types of channel interference are short term in duration such as traffic patterns, interference and shadow fading.
Therefore, there is a need for dynamic channel assignments for wireless networks, full automation, easy system growth and higher capacity.